Study says casual marijuana use may change brain
As more states move towards legalization of some form of marijuana use, a new study contends that even casual pot smokers may experience brain changes that affect emotion and motivation.
Previous studies have linked heavy marijuana use with impaired motivation, attention, learning and memory, but it has long been believed that casual use of the drug did not have negative consequences.
For the study, published in the Journal of Neuroscience, researchers used magnetic resonance imaging (MRI) to look at the brains of 40 participants between the ages of 18 and 25, who smoked pot at least once a week. They then compared those scans to the brain scans of people with little or no history of marijuana use.
A psychiatric evaluation ruled out that any of the participants were addicted to marijuana, yet the scans showed significant brain differences between the two groups. Compared to the non-users, the marijuana users had a larger nucleus accumbens, which is involved in reward processing. The brains of users also had an altered shape and structure. And, the more marijuana the person used, the greater these changes in the brain were.
Researchers say these changes could be an indication that the brain is forming new connections that promote further use of marijuana.